An architectural oddity hides in plain sight on this iconic London bridge.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

The bronze uniforms commemorate the vital role of women during World War II.

The last four extravagant street signs of London's historic banking street.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

A mysterious pair of mice eating a piece of cheese is London's smallest public sculpture.

The Great Fire of London and the regulation of one-way streets both started in this alley.

The commemorative stone column conceals a secret laboratory.

The 2,000-year-old beam is tucked within the pedestrian entrance to the old London Bridge.

Only a few pieces remain of the structure that carried people and goods across the Thames for some 600 years.

This one has sailed five times as far as Sir Francis Drake's famous ship.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

This unique bridge curls up like a caterpillar to let boats pass and then unfurls again to span a small canal.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

The final resting place of a space program monolith.

The blinking light atop the iconic landmark has been sending secret messages for decades.

High on a hill overlooking Los Angeles lives a world famous, high power conical Tesla Coil.

Horse cemetery on the grounds of Blarney Castle.